<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box {
            width: 200px;
            height: 200px;
            background: tomato;
            transition: width 3s cubic-bezier(0.21, -0.97, 0.82, 2.15) 0s;
        }
        .box:hover {
            width: 400px;
            height: 400px;
            background: skyblue;
        }
    </style>
</head>
<body>
    <div class="box"></div>
</body>
</html>